Light-based method for the endovascular treatment of pathologically altered blood vessels

ABSTRACT

A light-based method of endovascular treatment, in particular, of pathologically altered blood vessels. Provided are a Method of Endovascular Light Treatment and a corresponding Endovascular Light Application Device.

RELATED APPLICATIONS

This patent application is a continuation of and claims priority to PCTPatent Application No. PCT/EP2009/003027, entitled “Light-Based Methodfor the Endovascular Treatment of Pathologically Altered Blood Vessels,”filed Apr. 24, 2009, which claims priority to U.S. Provisional PatentApplication No. 61/047,779 filed Apr. 25, 2008. The complete disclosureof each of the above-identified priority applications is hereby fullyincorporated herein by reference.

The following presents a new, light-based method of endovasculartreatment, in particular of pathologically altered blood vessels.Provided are a Method of Endovascular Light Treatment and acorresponding Endovascular Light Application Device.

INTRODUCTION

All sorts of different therapy options are available to the therapistfor the treatment of pathologically altered blood vessels. In additionto the classic surgical methods, endovascular therapies have becomeincreasingly important in recent times. In particular, light-basedendovascular thermal methods for the obliteration of, for example,insufficient truncal veins have been integrated into the broad spectrumof therapy options for a few years. One of these light-based thermaltherapies is Endovascular Laser Therapy (ELT). In this, certain lightapplication systems are placed in the blood vessel which emit therapylight onto the wall of the blood vessel. The therapy light is absorbedby the tissue and/or blood, which causes the vein wall to heat up,leading in turn initially to a thermal necrosis of the cells in theblood vessel wall with a collagen contraction and wall thickening,usually followed by a thrombotic closure of the treated vein. Thesubsequent inflammatory reaction and repair processes lead, sometimesnot before after a number of weeks, to the obliteration of the truncalvein that has been treated and thus to the hemodynamic disconnection ofthe treated vein segment and branch varicose veins that were supplied bythis.

STATE OF THE ART

The aim of endovascular therapy is inter alia to close pathologicallyaltered blood vessels using a minimally invasive method. A procedurecurrently known and practiced to achieve this therapeutic aim is asfollows: After puncturing the vessel to be treated, a simple fiberglassor complex-structure energy applicator or light applicator is positionedintravenously usually via a type of catheter system using a sort ofSeldinger technique and therapeutic light is applied in this way. Beforeor during the treatment, however, the catheter system, which is onlyused for positioning, is generally pulled out of the vessel along withthe light applicator, whilst emitting the laser light. It is assumedthat the blood vessel closes immediately with this treatment method,especially because of the instant contraction and/or the formation of athrombus. With this method, the light is usually applied to a limitedarea of the vessel during a short period of time.

These systems of the prior art, especially within ELT, often suffer fromhigh local temperatures of several 100° C. up to more than 1000° C. Thisleads to a variety of problems, including protein agglomeration oraggregation, carbonizing of organic material or unwanted destruction orperforation of healthy structures or ingredients of body fluid or evenof the applicator. This may lead to clinical complications such ashematomas, phlebitis, erythema, ecchymosis and other lesions of tissues,e.g. also at nerves, or even unspecific pain.

When applying the Seldinger Technique, the desired vessel or cavity ispunctured with a sharp hollow needle, also called access needle ortrocar, optionally with ultrasound guidance if necessary. Commonly around-tipped guidewire is then advanced through the lumen of the accessneedle, and the access needle is withdrawn. The catheter or “cathetersheath” is inserted along the guidewire into the cavity or vessel,optionally after enlarging the puncture channel employing a dilator.After final introduction of the catheter sheath, the guidewire iswithdrawn.

Ultrasound guidance or fluoroscopy may be used to confirm the positionof the catheter and to manoeuvre it to the desired location. Injectionof radiocontrast may be used to visualise organs. Interventionalprocedures, such as thermoablation, angioplasty, embolisation or biopsy,may be performed.

Upon completion of the desired procedure, the sheath is withdrawn. Incertain settings, a sealing device may be used to close the hole made bythe procedure.

In the prior art the light emitting part of the light applicator,usually a special fibre tip or especially a bare fibre tip, is alwaysshifted through the open distal end of the catheter (catheter sheath)and is used in contact with the vessel and/or fluid within the vesselwithdrawing applicator and catheter (catheter sheath) together whileapplying light.

Other approaches of the prior art directly introduce the lightapplicator only into the vessel. This is an one step technique. Uponpercutaneous puncture of the vessel, the light applicator is introducedinto the vessel and moved to the location of interest within the vessel,often with ultrasound guidance and while the light applicator is movedback (in direct contact with the vessel or fluid within the vessel)light energy is applied to the length of the vessel that shall betreated. A repeated moving of the light applicator to the same positionis impossible. A punctual adhesion of tissue or blood on the surface ofthe applicator may even lead to a local overheating of the vessel or theapplicator.

WO99/12489, U.S. Pat. No. 7,396,355, U.S. Pat. No. 6,752,803 and U.S.Pat. No. 6,258,084 disclose an electrocatheter suitable for shrinkingblood vessels upon applying energy. The catheter comprises workingelectrodes, which are—when used—expanded from the catheter and are indirect contact with the blood vessel to be treated. In use, a tumescentfluid is injected into the tissue surrounding the treatment site. Afurther development of this electrocatheter is disclosed in WO 00/10475,U.S. Pat. No. 6,769,433 and U.S. Pat. No. 7,406,970. The electrode isput in apposition with the vessel wall and the wall is pre-shaped beforeapplying energy to the electrodes.

WO 2007/014063 discloses a catheter including a therapeutic element,such as a resistive heating element usable to deliver energy forligating, or reducing the diameter of a vessel.

US20060069417 discloses a catheter, which introduces electrodes in avein for a minimally invasive treatment of venous insufficiency by theapplication of energy to cause selective heating of the vein. Thecatheter is positioned within the vein to be treated, and the electrodeson the catheter are moved toward one side of the vein. RF energy isapplied in a directional manner from the electrodes at the working endof the catheter to cause localized heating and corresponding shrinkageof the adjacent venous tissue.

WO00/44296 and EP 1156751 B1 disclose an endovascular laser device fortreating varicose veins. The device of EP 1156751 B1 comprises a

-   -   a) laser of a wavelength in the range 500-1100 nm, which        delivers laser energy in bursts and is arranged to emit laser        energy to cause thermal damage to a vein wall so as to result in        a subsequent decrease in the diameter of said vein;    -   b) a fibre optic line; and    -   c) an angiocatheter for insertion into a blood vessel,        wherein said angiocatheter and said fibre optic line are        arranged and adapted such that in use said fibre optic line        makes intraluminal contact with a vein wall and said fibre optic        line ends in a bare tip and the tip of said fibre optic line is        arranged and adapted to be in direct contact with said vein wall        during treatment of said vein.

However, similar to the other catheters of the prior art, in whichenergy is applied upon contacting an energy or light applicator to theinterior wall of the vessel, this device of EP 1156751 B1 may causeunwanted damage to the interior wall of the vessel to be treated due tothe exposure of the fibre optic line to the vessel wall. In addition,when in use the free fibre optic line of EP 1156751 B1 may cause painand small injuries such as perforations and hematomas. Moreover, thereis a risk that the fibre optic line breaks during treatment and may belost, at least partially, in the vessel.

Thus, there is a need in the art to provide an improved device forintraluminal treatment of blood vessels, which allows a safer treatmentof patients, reduces risks and pain and preferably allows a bettercontrolled application of light energy to the blood vessels.

SUMMARY OF THE INVENTION

To fulfill this need, the present invention provides a blood vesseltreatment device comprising: a light applicator connected to the lightemitting unit, and a catheter/applicator tube for inserting the lightapplicator into and for guiding the light applicator within a vessel,wherein said catheter and said light applicator are arranged and adaptedsuch that in use at any time said light applicator does not makeintraluminal contact with any vessel wall and the light applicator iscapable of delivering light energy through the sheath of the catheter soas to emit light energy to cause damage to a vessel wall, preferably soas to result in a subsequent decrease in the diameter of said vessel.

This device surprisingly overcomes the problems in the art arising fromapplying high energy densities while contacting the light applicatordirectly to the vessel, such as high local temperatures, proteinagglomeration or aggregation, carbonizing of organic material orunwanted destruction of healthy structures or ingredients of body fluidor the applicator itself. Surprisingly, although the catheter is notremoved until the application of energy to the vessel has been completed(i.e. the catheter is still in place while the applicator has alreadybeen removed), the vessel—upon removal of the catheter—shrinks orcollapses as intended.

With this surprising solution, also vessels may be treated safely, whichencompass many bendings or vessels at bends or at constrictions may betreated, since the catheter protects the vessel from the risk of localdamage arising from contact with the light applicator. Also a punctualadhesion of tissue or blood on the surface of the applicator ismethodically and technically excluded, inhibiting local overheating ofthe vessel or the applicator.

Even if the light applicator should be damaged, the catheter protectsthe vessel from damage. In case of break-down, the fragments of thelight applicator can be easily withdrawn from the vessel, since theyremain inside the catheter.

The skilled person may easily control and/or optimize the result of thetreatment. In a preferred embodiment, thus, an ultrasound or radioactiveimaging unit for imaging the treated vessel and/or a temperature orcoagulation detecting unit are placed within the catheter.

The device is preferably a sterile device. Sterilization and reuse ofthe applicator is comparatively easy, since the light applicator is notin contact with body fluids, tissue or the vessel to be treated.

Two embodiments of the device are particularly preferred. In the firstembodiment, the device is open at the distal end and the catheter may beintroduced into the vessel employing the Seldinger Technique. In thesecond embodiment, the device is closed at the distal end and thecatheter may be introduced into the vessel in a one-step-process,without the need of using a wire guide. Both embodiments are describedin detail below and are exemplarily shown in FIG. 2.

The devices of these two embodiments may even be compatible with eachother, i.e. the device of the present invention may such that it can beinserted employing both techniques. Accordingly, in a thirdembodiment—for the first time to our knowledge with the same device—achange between these two techniques even during the therapeuticintervention is possible; just the catheter has to be changed or only tobe modified, e.g. cut, at the tip.

In addition, a kit is provided comprising one or more light applicators,e.g. for different purposes or different laser units; a catheter forinserting the light applicator into and for guiding the light applicatorwithin a vessel; a guide wire; and an access needle, wherein saidcatheter and said light applicator are arranged and adapted such that inuse at any time said light applicator does not make intraluminal contactwith any vessel wall and the light applicator is capable of deliveringlight energy through the sheath of the catheter so as to emit lightenergy to cause damage to a vessel wall, preferably so as to result in asubsequent decrease in the diameter of said vessel.

Also provided is a method of applying light energy from a light emittingunit to a blood vessel, from within the vessel, the method comprisingthe steps of: introducing into the vessel the device as described above;and applying energy to the vessel until the vessel is damaged,preferably until the damage results in a decrease in the diameter ofsaid vessel; further provided is a method of damaging a vessel usinglight energy from a light emitting unit, the method comprising the stepsof: introducing into the vessel the device as described above; andapplying energy to the vessel until the vessel is damaged, preferablyuntil the damage results in a decrease in the diameter of said vessel.

In analogy to the embodiments of the device of the present invention,also the method of the present invention is represented by two preferredembodiments. In the first embodiment, the device is open at the distalend and is introduced into the vessel employing the Seldinger Techniqueor kind of Seldinger Technique. In the second embodiment, the device isclosed at the distal end and the catheter may be introduced into thevessel in a one-step-process, without the need of a wire guide.

All these methods allow for cosmetic treatment of varicose veins oralternatively the treatment of pathologically altered blood vessels formedical purposes.

However, with this new method, the light applicator is guided in thecatheter system for the duration of the therapy (e.g. with a speed ofapprox. 1-5 mm/s) and the catheter itself is only pulled out of thevessel after completion of the light treatment, preferably until afterthe damaging of the vessel wall treated by (laser) light is achieved.Because the light applicator is guided in the catheter system, there isno direct contact between the light applicator and the blood vessel wall(see illustration in FIG. 1). In addition, with this measure, the vesselor vein to be closed is prevented, during the entire laser applicationby a sort of catheter system, from shrinking immediately or completelyclosing. This catheter system is therefore also a central component of asuitable blood vessel treatment device or light application system andlight is passed through it during the continuous or a section-wisetreatment. The catheter itself may also redefine or further optimize thedesired light emission properties of the light applicator. The bloodvessel is largely kept open for the duration of the therapy, and theimmediate closure of the vessel is prevented. The treated blood vesselmay only be obliterated after treatment when the catheter system isremoved.

DETAILED DESCRIPTION OF THE INVENTION

In one aspect, the present invention provides a vessel treatment devicecomprising: a light applicator connected to the light emitting unit; anda catheter for inserting the light applicator into and for guiding thelight applicator within a vessel, wherein said catheter and said lightapplicator are arranged and adapted such that in use at any time saidlight applicator does not make intraluminal contact with any vessel walland the light applicator is capable of delivering light energy throughthe sheath of the catheter so as to emit light energy to cause damage toa vessel wall, preferably so as to result in a subsequent decrease inthe diameter of said vessel.

The device is suitable to treat any hollow vessel in a mammal,preferably in a human.

The “vessel” may be any hollow anatomical structure. In a preferredembodiment, the vessel is a blood vessel, most preferably a vein.

Conditions of said vessel to be treated in line with the presentinvention encompass the treatment of varicose veins for cosmetic and/ortherapeutic purposes and, optionally, in connection with a tumescencelocal anesthesia. Also in line with the present invention is a single ormultiple treatment of a vessel by photodynamic therapy.

Preferably, the vessel treatment device further comprises a lightemitting unit, said light emitting unit being connected to the lightapplicator. The light may be laser light. The light emitting unit may bea laser, e.g. a pulsed laser or CW laser, or another means for inducinga thermal effect and/or a photodynamic effect. Any conventional orcommercially available laser may be employed.

In many embodiments of the present invention, the wavelength of thelaser light or emitted by the laser is in the range of about 500-2000 nmreferring to the optical properties of tissue, preferably in the rangeof 700-1500 nm.

The Power of the light emitting unit, e.g. of the laser, may be in therange of 1 to 150 W, preferably in the range of 10 to 50 W, morepreferably 15 to 40 W.

The Energy and the power density applied per cm² at the emitting surfaceor emitting area of the light applicator is much lower (at least 1 to 3magnitudes lower) than in conventional applicators, since the energyemitting part (“emitting surface” or “emitting area”) of the applicatoris much larger than in the prior art, where only a bare fiber or otherlocally very confined tip area emits light. According to the inventionthe length of emitting surface or emitting area is preferably in therange of 3 to 70 mm, more preferably in the range of 10 to 30 mm. In apreferred example the emitting part is about 25 mm long. The area of theemitting surface or emitting area of the light applicator is in therange of 0.1 cm² to 10 cm², preferably 0.5 cm² to 5 cm², most preferably1 cm² to 3 cm². The power density at the emitting surface or emittingarea of the light applicator is in the range of 1 to 200 W/cm²,preferably 10 to 100 W/cm², and most preferably 20 to 35 W/cm².

Also the radiation profile and the easy movability of the lightapplicator may be adapted to allow to overcome the disadvantages of thepoint-shaped energy application of the prior art, e.g. proteincarbonization. The overall energy needed can be better controlledemploying the movable light applicator and/or the radiation profile ofthe present invention.

The light applicator is connectable to the light emitting unit. In oneembodiment, the light applicator is a fibre optic line, preferablycomprising a light applicator tip or a fibre optic tip, most preferablya cylindrical diffuser.

The light applicator may have a length of e.g. 10 to 500 cm, preferably30-300 cm, more preferably, 200-300 cm. This applies in particular, ifthe light applicator is a fibre optic line.

The diameter of the light applicator may e.g. be between 0.1 and 2.5 mm,preferably in the range of 0.3 to 1.9 mm, more preferably in the rangeof 0.5 to 1.8 mm, even more preferably in the range of 0.7 to 1.7 mm,even more preferably in the range of 1.0-1.6, most preferably in therange of 1.1 to 1.2 mm. This applies in particular, if the lightapplicator is a fibre optic line. The diameter of the catheter is alwaysa bit (approximately 0.1 to 2 mm) bigger than of the corresponding lightapplicator. A catheter, which is inserted using the Seldinger Technique,is normally of a larger diameter compared to a catheter inserted in aone step procedure.

In one embodiment, the diameter of the fibre optic tip is between 0.1and 2.5 mm, preferably in the range of 0.6 to 2.4 mm, more preferably inthe range of 1.0-2.3 mm; even more preferably in the range of 1.3 to 2.2mm, even more preferably in the range of 1.4 to 2.1 mm; even mostpreferably in the range of 1.5-1.9 mm.

The light applicator may be of a uniform cylindrical shape. In oneembodiment, the light applicator emits light in a cylindrical, ideallyradial profile.

In one embodiment, the light applicator comprises light emitting areas,which are locally or systemically distributed in front of the fibresurface and are capable of emitting light more or less perpendicular tothe fibre axis. Preferably, the light emitting areas are placed at thedistal end of the light applicator and extend over 1 to 10 cm,preferably 2 to 5 cm. The light emitting areas may comprise scatteringparticles.

FIG. 3 shows a homogeneous and an inhomogeneous cylindrical radiationprofile.

The homogeneous cylindrical radiation profile preferably has a lengthalong the axis of 1 to 5 cm, more preferably 2 to 4 cm, most preferably2 to 3 cm. This leads to a reduced light intensity, as compared to theprior art, which conventionally employs a non-areal, but point-shapedlight emission by a optic fibre laser tip, thereby applying very highlocal intensities.

In particular embodiments, an inhomogeneous distribution may bereasonable to further reduce the total necessary light energy. At theproximal end of the emitting area more light is applied as at the distalend. This mode of emitting light, causing fast preheating of the tissueat the proximal end, saves energy since the total energy required issomewhat lower when compared to homogenous profile, as e.g. shown inFIG. 3 a. The exact shape of the preferred embodiment is a kind ofexponential decay, as this can be easily realized by volume scattering.Also the inhomogeneous cylindrical radiation profile preferably has alength along the axis of 1 to 5 cm, more preferably 2 to 4 cm, mostpreferably 2 to 3 cm.

The catheter is for inserting the light applicator into the vessel andfor guiding the light applicator within the vessel. In general, anyconventional catheter may be employed, as long as this catheter ishighly transparent for the therapeutic light and inter aliaphotochemically inert. In preferred embodiments, it is made of Teflon orPTFE. Wherever reference is made to a “catheter”, this is meant toencompass also any applicator tube in general.

Preferably, the catheter, in particular the sheath of the catheter, i.e.its tubular envelop, is partially, more preferably fully opticallytransmissible for light emitted from the light applicator. The surfaceof the catheter or the sheath of the catheter may have a coating, e.g. ahydrophilic coating. A hydrophilic coating allows for easier inset intoand removing out of the blood vessel. Preferably, the distal end of thecatheter is closed. More preferably, also the sheath of the catheter iscylindrical and fully optically transmissible for light emitted from thelight applicator. The sheath of the catheter may even help, e.g. tohomogenize, the radiation profile.

Catheter and light applicator are arranged and adapted such that in useat any time said light applicator does not make intraluminal contactwith any vessel wall. Preferably the light applicator is placed withinthe sheath of the catheter, and may be flushed, preferably by atransparent physiological solution. Here, the catheter may be open to orin open contact with the fluid within the vessel, although the lightapplicator does not protrude from the catheter or the catheter sheathand stays safely secured inside the catheter.

If the catheter is open, the device may be introduced employing theSeldinger Techniques, i.e. using a guide wire in analogy to classicalinsertion processes of the prior art as explained above. However, inthis invention, the light applicator is not shifted through the opendistal end of the catheter so that the light applicator does not makeintraluminal contact with the vessel, i.e. the applicator does not makeintraluminal contact with any vessel wall (see also FIG. 2, “principleA”). The catheter in this embodiment is flushable and flushing fluid,preferably an aqueous solution, more preferably a physiological solutionmay be used to clean and/or cool the light applicator.

If the catheter is closed, the device may be introduced employing a onestep technique, i.e. without using a guide wire. After puncture of thevessel, the catheter is inserted into the vessel (see also FIG. 2,“principle B”). This is contrary to the prior art, wherein only thelight applicator is introduced in such a one step technique, but not acatheter bearing the light applicator. The catheter may or may notencompass the light applicator during the insertion step depending onthe rigidity of the device encompassing catheter and light applicatorneeded. The catheter alone is more flexible, while catheter togetherwith light applicator is a more rigid unit.

In preferred embodiments, the light applicator is intended not to be incontact with blood when in use. These embodiments minimize the risk tocreate carbonization effects in the vessel, since neither vessel, norblood are in contact with the light applicator and there is no primaryheat of the light applicator as energy is transferred by the emittedlight. Also secondary heat within the applicator can be attenuated givenby the spacing between light applicator inside the catheter and the(part of the) vessel to be treated.

The minimal distance from the light applicator tip to the distal end ofthe catheter is in the range of 1.0 to 30 mm, preferably in the range of2.0 to 20 mm, more preferably in the range of 3.0 to 10 mm, mostpreferably in the range of 5.0 to 8.0 mm.

The light applicator is capable of delivering light energy through thesheath of the catheter and to cause damage to a vessel wall. Thisdelivering of light energy preferably results in a subsequent decreasein the diameter of said vessel wall; most preferably until the shrinkageor collapse of vessel wall.

The light applicator during use may be placed repeatedly at the sameposition within the vessel with or without moving the catheter.Preferably, the light applicator is movable within the catheter; morepreferably the light applicator is movable within the catheter when inuse. Most preferably the light applicator is movable with constantvelocity, e.g. with a velocity of 1 to 5 mm/s, preferably 1.0 to 4.0mm/s, more preferably 2.0 to 3.0 mm/s; most preferably, the velocity iscontrolled by a velocity control unit.

It is also conceivable that the catheter and light applicator are movedtowards each other at different speeds.

Visible pilot light, coupled into the applicator, could also be used,for example, to determine the position of the light applicator. Othertypes of labels may be used alternatively, e.g. fluorescent markers.

In a preferred embodiment, the blood vessel treatment device of theinvention further comprises an ultrasound, magnetic resonance orradioactive imaging unit for imaging the vessel to be treated; and/or avelocity control unit for controlling the velocity with which the lightapplicator is moved within the catheter and/or a temperature orcoagulation detecting unit inside the catheter for determining thetemperature or tissue properties at the position, where the vessel isdamaged and/or an imaging unit, connected to the one or more of thethree units above for displaying the data measured by these one or moreunits. In addition a closed loop unit may be present based on theimaging unit, which closed loop unit provides a feedback controlling theparameters light intensity and/or velocity or segmentation of movement.“Segmentation of movement” means that the light applicator is movedstepwise, i.e. moved to one position in the catheter, keep for a shorttime interval and moved to a next position, and so on.

The temperature when using the device of the present invention ispreferably kept in the range between 37° C. and 200° C., more preferablybelow 150° C., most preferably below 100° C. Each position is preferably“heated” by employing the light applicator for 1 to 25 s, morepreferably 2 to 15 s, most preferably 5 to 10 s. This time range helpsto allow a mild treatment, thereby avoiding high temperatures. If moreenergy needs to be applied to a particular position in order todeliberately damage or shrink the vessel, the light applicator can bemoved and used several times to treat the same position.

In its second aspect, the present invention provides a kit comprisingone or more light applicators; a catheter for inserting light applicatorinto and for guiding the light applicator within a vessel; a guide wire;and an access needle, wherein said catheter and said light applicatorare arranged and adapted such that in use at any time said lightapplicator does not make intraluminal contact with any vessel wall andthe light applicator is capable of delivering light energy through thesheath of the catheter so as to emit light energy to cause damage to avessel wall, preferably so as to result in a subsequent decrease in thediameter of said vein wall. The kit may be used to prepare the device ofthe first aspect of the present invention and to insert said deviceemploying the Seldinger Technique.

In its third aspect, the present invention provides a method of applyinglight energy from a light emitting unit to a vessel from within thevessel, the method comprising the steps of: introducing into the vesselthe device of the first aspect of the invention and applying energy tothe vessel until the vessel is damaged or collapses. While the lightemitting unit may be introduced into the vessel, e.g. in a miniaturizedversion, it is preferred herein that “introducing into the vessel thedevice of the first aspect of the invention” means that only thecatheter and the light applicator are introduced into the vessel and thelight emitting unit, if part of the device, is connected thereto, butstays outside the vessel.

“Collapse” or “collapse of the vessel” in particular means that thestructure of the vessel, in particular of the wall of the vessel isdestroyed, preferably so as to close the vessel from any flood of fluid,preferably from flood of blood.

“Damage” or “damage of the vessel” preferably means that the structureof the vessel, in particular of the wall of the vessel is altered in itsgeometry and/or stability. Preferably, the diameter of the vesseldecreases when damage of the vessel occurs. In one embodiment, thevessel decreases in its diameter to less than 90% of the originaldiameter, i.e. before start of applying energy, preferably, the vesseldecreases in its diameter to less than 85%, to less than 80%, to lessthan 75%, to less than 70%, to less than 65%, to less than 60%, to lessthan 55%, to less than 50%, to less than 45%, to less than 40%, to lessthan 35%, to less than 30%, to less than 25%, to less than 20%, to lessthan 15%, to less than 10%, to less than 5%, to less than 4%, to lessthan 3%, to less than 2%, to less than 1% of the diameter beforeapplying the light energy, most preferably it shrinks until the vesselis closed or until no fluid or blood can flow through at the damagedposition (“obliteration”).

Optionally, perivenous tumescence may be used to support the treatment,preferably by administering local anesthesia and/or for reducing therisk of damaging of surrounding tissues, in particular nerve tissues.

Upon finalizing the vessel treatment, shrinkage or damaging, thecatheter is withdrawn from the vessel. This may be guided with optical,radioactive or acoustic labels, preferably placed at the distal end ofthe catheter.

The method of this third aspect of the invention may also be used fordamaging a vessel using light energy from a light emitting unit.

In one embodiment, the method of this third aspect of the invention,further comprises the step of placing the light applicator repeatedly,i.e. at least twice, at the same position in the catheter and therewithin the vessel while continuing to apply energy to the vessel. This mayallow for a safer and more regular treatment of the vessel. Preferably,the method comprises the step of moving the light applicator in thecatheter and therewith in the vessel while continuing to apply energy tothe vessel.

In many embodiments, the method of this third aspect of the inventioncomprises imaging the vessel to be treated, controlling the velocitywith which the light applicator is moved within the catheter, ordetermining the temperature or tissue properties at the position, wherethe vessel is damaged.

APPLICATIONS OF THE PRESENT INVENTION

In particular, the device and method of the present invention can beused in the treatment of varicose veins and, in particular, inconnection with a tumescence local anesthesia.

In the treatment of varicose veins, the shrinking and/or closure of thevein is brought about by a combination of spontaneous contraction,thrombotic closure (on a comparatively small scale) and later fibrotictransformation of the blood vessel and support by secondary effects(such as wound healing). These biological effects are primarily inducedthrough the effect of heat. The absorption of light which causes warmingoccurs here both in the blood and on the vein wall itself.

The embodiments of the present invention as set forth above, offer theadvantages over other techniques in the art in clinical use as follows:

-   -   The application system can be introduced into the blood vessel        using the Seldinger technique or a modification of the Seldinger        technique or directly by using a closed catheter.    -   During the introduction of the system by Seldinger technique and        application of light, the application system can be rinsed via        the catheter, e.g. to allow cooling.    -   During the treatment, the blood vessel wall can be irradiated in        several sections, i.e. after a section has been irradiated, the        application system is steadily moved forward by roughly the        length of this section. It is also conceivable that the outer        catheter and inner application parts are moved towards each        other at different speeds. Visible pilot light, coupled into the        applicator, could also be used, for example, to determine the        position of the light applicator.    -   The closure of the blood vessel after the light treatment        presented here can be supported by additional secondary measures        such as compression.    -   In addition to thermal laser applications, this method can also        be used for photodynamic applications.    -   There is almost no risk of unwanted damaging of the vessel to be        treated especially due to comparatively extremely low light        power densities used, the avoidance of contact and the constant        friction between applicator to be moved and catheter without be        changed during the application of energy

FURTHER EMBODIMENTS

Ideally, the light in the method described here is emitted on a circularbasis and preferably over a particular length. This ensures a more eventreatment of the blood vessel. In addition, a cylindrical irradiationover a length of approx. 0.5-5 cm can sensibly balance out lack ofhomogeneity in the vessel wall and/or irregularities caused by movementof the applicator.

In addition, this applicator may have a higher level of light emissionat the proximal end of its irradiation area. This causes a higher levelof energy to be given off at the proximal end of the irradiation areawhen the light applicator is withdrawn than at the distal end. Thismeans that, when the proximal end passes by, the blood vessel wallsection being passed by the light applicator quickly heats up from bodytemperature (approx. 37° C.) to treatment temperature (approx. 60-100°C.). When the distal applicator end passes by, the temperature of theblood vessel wall is not increased dramatically any further, but simplyremains constant. This rapid preheating can increase the efficiency ofthe method as a whole (by minimizing the transport of heat and bychanging the optical parameters during preheating).

-   -   Suitable wavelengths for the therapy light used in this method        are in the visible to infrared range, especially because of the        optical absorption and dispersion in the tissue between 500-2000        nm.    -   The method can be optimized on the basis of an online        temperature or tissue properties or geometrical measurement        during irradiation or in breaks between irradiation in or on the        surface of the application system, or even supported by        regulating technology.        Advantages of the New Therapy Method Described Here    -   The low-friction, even sliding of the light applicator in a type        of catheter system during treatment makes it easier for the user        to achieve an even treatment result.    -   Because the catheter remains in the blood vessel during        treatment, a defined positioning (minimum distance/centering) of        the light applicator is ensured, especially at bends.    -   With this method, it is possible to treat certain sections of        the vessel or the blood vessel over the entire length to be        treated several times over. This means that it is possible to        achieve closure gently, through several applications of low        doses of light or—if therapy monitoring through parallel        diagnostic methods is possible—to optimize the treatment result        during the intervention.    -   There is almost no possibility of creating primary thromboses.        In particular, with this method, it is not possible to create a        carbonized coagulation of blood on the light applicator itself,        which could cause indirect thermal damage or even perforation of        the blood vessel wall.    -   Because, with this method, the light-emitting area of the        applicator is not in direct contact with the blood, the        treatment is more even over the entire length of the blood        vessel. The light-emitting area is not changed through any        adhesion of blood and/or tissue to the outside of the        application system for the entire duration of the treatment.    -   With this method, the catheter, which remains in the vessel        until the treatment is finished, represents an additional safety        factor for the method. If any incident occurs, such as damage to        the applicator at its light-emitting area, the entire system can        be retrieved without parts being left in the body of the        patient.

DESCRIPTION OF THE FIGURES

FIG. 1 shows the positioning of the catheter system (2) and the lightapplicator (3) with light-emitting area (4) in the blood vessel (1). Thelight emitting area may be a part of or an extension of an optic fibre.

FIG. 2 shows schematically a possible introduction of the device of thepresent invention using a two step process (“principle a”) employing theSeldinger technique. Upon puncture with an access needle, a guide wireis inserted into the vessel through the access needle. The guide wireguides the catheter, which is inserted starting with the (open) distalend along said guiding wire. Upon positioning the catheter, the guidewire is removed and the light applicator is inserted into the catheterand used to apply energy. The light applicator may be movable within thecatheter and is capable of emitting light through the catheter, e.g.also through the open distal end yet especially through the sheath ofthe catheter in a cylindrical manner. Upon finalizing the treatment, thelight applicator may be removed from the catheter. Finally. the catheteris removed from the vessel.

FIG. 2 also shows the introduction of the device of the presentinvention using a one step process (“principle b”). The catheter itselfis used as “guide wire” upon puncture with an access needle and guidesthe light applicator through the vessel. Here, both are insertedsimultaneously. However, in accordance with the present invention, thelight applicator may also be inserted subsequently to the insertion ofthe catheter. Upon positioning the catheter, the light applicator isused to apply energy. The light applicator is movable within thecatheter and is capable of emitting light through the catheter, e.g.through the closed distal end and/or especially through the sheath ofthe catheter in a cylindrical manner. Upon finalizing the treatment, thelight applicator may be removed from the catheter. Finally, the catheteris removed from the vessel.

Inserting the catheter with or without the light applicator may dependupon the rigidity needed. The catheter alone is more flexible, whilecatheter together with light applicator forms a more rigid unit.

FIG. 3 shows exemplary radiation profiles of the light applicator inuse. Here, the light applicator is a cylindrical diffuser based on aconventional optical fibre 5. The upper graph shows a homogeneouscylindrical radiation profile. The lower graph shows an inhomogeneouscylindrical radiation profile. The profiles can be created for exampleby the arrangement of different concentration of volume scatteringlayers (c₁ to c_(n) in the Figure) as desired.

The figure shows different scatter layers c₁ to c_(n), each comprising amedium with scattering particles 6) which may be used to set up theradiation profile by coupling out a distinct portion of light.

The device in FIG. 3 also shows an embodiment, which comprises a closure7 of the light applicator. Here, e.g. an ultrasound or x-ray label maybe placed within the applicator yet outside the light-emitting regionfor not being absorbing.

The invention claimed is:
 1. A blood vessel treatment device, comprising: a light applicator; and a catheter, comprising a sheath, via which the light applicator is inserted into and guided within a blood vessel, wherein the sheath is flexible and non-expandable in the radial direction along an entire length of the sheath, wherein the catheter is open at a proximal end of the catheter, and wherein the catheter is closed at a distal portion of the catheter; and wherein the catheter and the light applicator are arranged and adapted such that, at any time during use, the light applicator does not make intraluminal contact with any vessel wall and the light applicator is capable of delivering light energy through a sheath of the catheter so as to emit light energy and cause damage to a vessel wall of the blood vessel, the damage resulting in a subsequent decrease in a diameter of the blood vessel, during use, the light applicator is movable within the catheter in consecutive segments or at a constant velocity of 1-5 mm/s, and during use, the light applicator may be placed repeatedly at the same position within the vessel without moving the catheter.
 2. The device of claim 1, further comprising a light emitting unit, said light emitting unit being connected to the light applicator.
 3. The device of claim 1, wherein the light energy is laser light energy of a wavelength in the range 500-2000 nm.
 4. The device of claim 1, wherein the light applicator is placed within the sheath of the catheter.
 5. The device of claim 1, wherein the light applicator is capable of delivering light energy to the blood vessel using the Seldinger Technique or a kind of Seldinger Technique.
 6. The device of claim 1, wherein a diameter of the light applicator is between 0.1 and 2.5 mm, a length of a light emitting surface of the light applicator is between 3 to 70 mm, and a power density of the emitting surface of the light applicator is between 10 to 100 W/cm².
 7. The device of claim 1, wherein the light applicator comprises a fiber optic line and cylindrical diffuser.
 8. The device of claim 7, wherein the cylindrical diffuser emits light in an inhomogeneous profile such that more light energy is provided at a distal end than a non-distal end of the light applicator.
 9. The device of claim 7, wherein the cylindrical diffuser emits light in a homogeneous profile over the surface of the cylindrical diffuser.
 10. The device of claim 7, wherein the entire sheath of the catheter comprises a tubular envelope of consistent diameter, and a distal end of the catheter is closed by a closure, a diameter of the closure being substantially equivalent to the diameter of the sheath of the catheter.
 11. The device of claim 1, wherein the light applicator emits light in a cylindrical radiation profile.
 12. The device of claim 1, further comprising at least one of: a contrast unit that captures images of the blood vessel to be treated; a velocity control unit that controls a velocity at which the light applicator is moved within the catheter; a temperature detecting unit that determines a temperature at a position where the blood vessel is to be damaged; a coagulation detecting unit that determines coagulation at a position where the blood vessel is to be damaged; an imaging unit that displays the data measured by at least one of the contrast unit, the velocity control unit, the temperature detecting unit, and the coagulation detecting unit; and a closed loop unit that controls at least one of the parameters of light intensity, velocity, and segmentation of movement.
 13. The device of claim 1, further comprising: a velocity control unit that controls a velocity at which the light applicator is moved within the catheter; and a temperature detecting unit that determines a temperature at a position where the blood vessel is to be damaged.
 14. A kit, comprising: a light applicator; a catheter via which the light applicator is inserted into and guided within a blood vessel; and an access needle; wherein the catheter and the light applicator are arranged and adapted such that, at any time during use, the light applicator does not make intraluminal contact with any vessel wall and the light applicator is capable of delivering light energy through the catheter to emit light energy and cause damage to a vessel wall of the blood vessel, and a sheath of the catheter is flexible and non-expandable in the radial direction along an entire length of the sheath that is at least partially optically transmissible to emit light energy from the light applicator, wherein the catheter is open at a proximal end of the catheter, and wherein the catheter is closed at a distal portion of the catheter.
 15. The kit of claim 14, wherein the catheter comprises a single opening only, wherein the opining is at a proximal end of the catheter.
 16. A blood vessel treatment device, comprising: a light applicator; and a catheter via which the light applicator is inserted into and guided within a blood vessel, wherein the catheter and light applicator are arranged and adapted such that, at any time during use, the light applicator does not make intraluminal contact with any vessel wall and the light applicator is capable of delivering light energy through a sheath of the catheter so as to emit light energy and cause damage to a vessel wall of the blood vessel, the damage resulting in a subsequent decrease in a diameter of the blood vessel, and the sheath of the catheter is flexible and non-expandable in the radial direction along an entire length of the sheath that is at least partially optically transmissible to emit light energy from the light applicator, wherein the catheter is open at a proximal end of the catheter, and wherein the catheter is closed at a distal portion of the catheter. 